1 X-ray enhancement and long- term evolution of Swift J arXiv: Authors: O. Benli, S. Caliskan, U. Ertan et al. Reporter: Fu, Lei

2 Outline Introduction Long-term evolution of Swift J X-ray enhancement of Swift J Discussion and Conclusions

3 Introduction Swift J was discovered on 2011 July 14 a SGR-like burst and associate with outburst

4 Introduction The observation of ROSAT in –2.4 keV count rate 0.012

5 Introduction

6 Swift J is the second low-B magnetar Quiescent luminosity ~ erg/s

7 Introduction In magnetar model –toroidal and dipole fields of and

8 Introduction Rea et al. 2012

9 Introduction

10 Introduction This work –Fallback disk model –Determine the evolutionary epoch and the field strength of this source –Explain the X-ray enhancement of this source

11 Long-term evolution of Swift J Critical parameter –Initial surface density profile –Hot-Cold viscosity transition

12 Long-term evolution of Swift J –Initial outer disk radius –X-ray irradiation flux C~ –Mass transfer is conservative

13 Long-term evolution of Swift J The spin evolution –AXP/SGR are sources accreting in spin- down phase –accretion –accretion stops

14 Long-term evolution of Swift J in units of,except for dashed line P0=300ms

15

16 X-ray enhancement of swift J Disk piles up caused by the SGR burst

17

18 Discussion and conclusions the properties in quiescent state –accretion –no accretion

19 Discussion and conclusions Both the X-ray enhancement and long-term evolution can be explained in the frame of fallback disk model The model sources with the dipole field strength in the range on the pole of the star and with the initial periods greater than ~55ms can reach the X-ray luminosity and the rotational properties of Swift J simultaneously When accretion stop the variation in could be observed with out a significant change in the observed luminosity of the source

20 Quantum spindown of highly magnetized neutron stars arXiv: Authors: B. Lamine, C. Berthiere, A. Dupays Reporter: Fu, Lei

21 vacuum magnetized by the rotating dipole m --> due to retardation effect a spin-down torque will excerted on the NS the energy loss rate is

22 in the classical dipole spin down Spin evolution

23 when period derivative has minimum value when quantum contribution will be dominant

24 the evolution of crab pulsar in 50kyr

25 Constraints on the mass and radius of NS

26 Thanks